English physicist, mathematician, astronomer, natural philosopher, alchemist and theologian, his Philosoph√¶ Naturalis Principia Mathematica, published in 1687, is considered to be the most influential book in the history of science. In this work, Newton described universal gravitation and the three laws of motion, laying the groundwork for classical mechanics, which dominated the scientific view of the physical universe for the next three centuries and is the basis for modern engineering.

The best interpretation of the suite of data that we have in hand right now is that the stuff of which this telescope is made, of which you and I are made, ordinary atoms that we learned about in high school chemistry class comprises about four percent of the total matter and energy density of the universe that we live in.

The best interpretation of the suite of data that we have in hand right now is that the stuff of which this telescope is made, of which you and I are made, ordinary atoms that we learned about in high school chemistry class comprises about four percent of the total matter and energy density of the universe that we live in. And another quarter or so, more or less, is comprised of matter that creates gravity, that creates the forces that makes things go in orbits, but is not characterized by the atoms and their constituents that we know. And then three quarters, or thereabout, 70% of the mass energy is something that has been dubbed dark energy and seems to be forcing the universe as a whole to move apart to have distances stretched, to counter act the force of gravity, work against it and act like a pressure to make the universe fly apart yet faster than it is already expanding.

So this is a total mystery. These particles have not been detected in Earth-based laboratory, their theory has not found obvious mechanisms to explain whatís going on yet, and maybe thereís just a fundamental lack of understanding of how gravity works on a large scale and how our whole universe is structured. So itĎs a wonderful and exciting time when we are, the state of our field is dominated by forces and particles that we have never discovered and donít understand.

Eyes versus telescopesRichard Green
- Large Binocular Telescope (LBT)

Our eyeballs allow us to reconstruct the depth of the scene that we are seeing because they are spaced far enough apart that they give us a third dimensional view. Weíre not, these arenít nearly far enough apart to be interesting at the distance of astronomical objects.

Our eyeballs allow us to reconstruct the depth of the scene that we are seeing because they are spaced far enough apart that they give us a third dimensional view. Weíre not, these arenít nearly far enough apart to be interesting at the distance of astronomical objects. So we donít use it to reconstruct the third dimension, we use it to take advantage of the physics property of light and objects that limits how sharp a picture we can take. So weíre using the 23 meters from tip to tip to get the sharpest image that we can from this huge expanse.

So if our eyes could work together, with the spacing between our eyes is at least ten times larger than the opening of our iris. So if we could phase the light like that, like weíre doing with this telescope we could have vision, distant vision, that was ten times sharper than it is.

If our eyes could work like this telescope worked we would be taking advantage of collecting the light simultaneously in both of our eyes at once and using it as though we had one giant eye ten times larger than the eye we have, and the physics limitation of our eyes at the moment limits the resolution of the scene that we have, although our brains do a lot of compensating for that. So if our eyes worked like this telescope we could process to make our visual acuity ten times sharper at a great distance. Thatís what the telescope is performing.

The first time I looked through a telescopeRichard Green
- Large Binocular Telescope (LBT)

But the thrill of the first time I went when I entered graduate school and got to ride in the cage at the focus underneath the five-meter at Palomar, which was the worldís largest telescope, and look in an eye-piece and see a galaxy that looked as beautiful as a photograph.

So the very first time I looked through a professional telescope was kind of an anticlimax because we were actually making a measurement and we were looking at a star, and it was a star, and so it wasnít very exciting.

But the thrill of the first time I went when I entered graduate school and got to ride in the cage at the focus underneath the five-meter at Palomar, which was the worldís largest telescope, and look in an eye-piece and see a galaxy that looked as beautiful as a photograph that was the moment that said that not only is this field a thrilling intellectual exercise, itís aesthetically just gorgeous, and so I was hooked.

The GMT will be a telescope like this one but symmetric, filled in. So we have two eight-meter dishes, these mirrors, and thereís about eight meters in between them. So imagine filling in with two more eight-meter mirrors between these two on each side filling in the circle, plus one in the center. So that it wonít be any bigger across or not much bigger across than this one, but this one is like a one-dimensional version and that one will be the fully filled out version of the same kind of system.

The intention is ultimately to reach the diffraction limit with that telescope as well, so definitely interferometric techniques will have to be used to phase the light from each of the seven mirrors as though it was acting as one mirror.

It will be certainly a technology pathfinder for future large generation telescopes. On the other hand, we believe this one will have a rich history of scientific discovery on that same twenty-year timescale since itís breaking ground in ways that are unique because of its unique design.

How the Large Binocular Telescope (LBT) worksRichard Green
- Large Binocular Telescope (LBT)

Thereís lots to do and this telescope will work frequently in a mode where you use the two sides in parallel with identical or similar instruments to get twice as much information on the same field of view.

Two things have to happen. First of all, the telescope has to compensate for the blur of the earthís atmosphere in order to do that we use a system called adaptive optics, which has some flexible optical element in it that restores the natural shape of the light wave after its distortion by the Earthís atmosphere. This telescope is going to be unique in doing that by having the actual second mirror of the telescope itself be that correcting element. So the main reflecting piece of glass is 91 centimeters, 36 inches in diameter and 1.6 millimeters thick, itís like a tissue. It has 672 voice coil magnets and it changes its shape a thousand times a second on the basis of signals from analyzing the light from a star that has come through the atmosphere and has been distorted along the same path.

So each side will have an adaptive system making the first correction to the star light. Then the total light path has to be held constant to lock in the phase of the light waves, and so this huge rigid steel allows a very fixed formation to be held and then the rest is done by actively steering the mirrors to lock things in place. So the telescope mount itself needs to hold the relative position of the two light paths accurate to almost one micron, and then there is like a little slide trombone within the light combining instrument that does the fast rapid and last small correction to keep the phase locked, as we would say.

Thereís lots to do and this telescope will work frequently in a mode where you use the two sides in parallel with identical or similar instruments to get twice as much information on the same field of view. So thereís a tremendous demand for what we call seeing-limited and the natural blurred image or corrected by adaptive optics but with just one beam. However, this is just about the largest size mirror that can be easily made and transported to a telescope site. So to gain more aperture to look at yet fainter, more distant galaxies in more detail future telescopes will need to be constructed out of multiple elements like this one is with its two. So itís the first of the next generation of telescopes.

Somehow as human beings we are innately curious. We really want to understand more and more about the world we live in and our place in the broader universe in which this planet, sun and solar system sits.

Somehow as human beings we are innately curious. We really want to understand more and more about the world we live in and our place in the broader universe in which this planet, sun and solar system sits.

And so Galileo set such a standard of receiving information that was so contradictory to the accepted framework of thought and said we have to follow the evidence. We have to reconstruct a framework because this evidence is telling us how our world is actually organized. Well thatís an inspiration, that is what a strong basis for modern science where itís tempting to get comfortable in a framework of our understanding of the universe and then have that whole framework go up in smoke, such as the discovery of dark energy, which means we donít understand how the universe is actually structured at the moment.

And so that pushes us to more observations, more discovery, and more thinking. So itís a remarkable milestone, Galileoís looking out there and seeing moons moving around Jupiter with a real telescope, and we can only humbly follow in the kind of bold thinking that he was able to do in response to information like that.

International partnership of the LBTRichard Green
- Large Binocular Telescope (LBT)

This is an extraordinary international partnership that has conceived and financed and made successful this telescope project.

This is an extraordinary international partnership that has conceived and financed and made successful this telescope project. The initial members of the partnership were the University of Arizona and what is now all of Italian national astronomy but centered with a lot of the effort at the Arcetri observatory in Florence, and then later a collaboration of German research institutions joined largely from the Max Planck Society, but also including observatories in Heidelberg and Potsdam, historic places, and the partnership is rounded out by a group of US universities with powerful astronomy departments: Ohio State, Minnesota, Virginia, Notre Dame.

So itís an international partnership, public US institutions and powerful European research institutions. There is very little US government money involved, this has largely been state and private on the US side.

Projects that get as large as this one are unlikely to be done by single organizations and will require national or international partnerships for success.

Reflections on the International Year of AstronomyRichard Green
- Large Binocular Telescope (LBT)

I hope they realize that we are beings that were wired to live on a planet that has a dark night, and that if we donít protect that darkness and allow us, and children and grandchildren to at least experience it in special places, if not everywhere we live, then we will have lost a critical aspect of our being here.

I hope they realize that we are beings that were wired to live on a planet that has a dark night, and that if we donít protect that darkness and allow us, and children and grandchildren to at least experience it in special places, if not everywhere we live, then we will have lost a critical aspect of our being here.

We need to be able to look out at that night sky, see our Milky Way galaxy, see the faint stars that make up the constellations that our Greek predecessors saw and appreciate just intuitively the fact that we are a very small blue spec in this very large universe.

Survey astronomyRichard Green
- Large Binocular Telescope (LBT)

So a very promising line of investigation, which is already going forward is looking at the sound waves that rattled through the universe in its earliest moments and then got frozen in the matter when the radiation was allowed to free-stream and the matter was interacting with itself.

So a very promising line of investigation, which is already going forward is looking at the sound waves that rattled through the universe in its earliest moments and then got frozen in the matter when the radiation was allowed to free-stream and the matter was interacting with itself.

So these sound waves are actually imprinted in the large scale structure of galaxies and clusters of galaxies in the universe. And so big surveys are going to be underway to try to find that out, to look at these patterns and see if we can understand how dark matter, dark energy and ordinary matter interacted and learn some more about these forces and their hidden nature.

So then the follow up is going to happen on telescopes like this, where the properties of individual galaxies, their accurate red shifts, their clustering together at the earliest cosmic times can be explored in detail.

Why the challenge of building the LBT?Richard Green
- Large Binocular Telescope (LBT)

It is all about the science. The astronomers are eager to find out about how planet systems were formed around stars. They want to probe into the hearts of galaxies and see the regions right around the black hole that's accreting material and ultimately shining away as a quasar.

It is all about the science. The astronomers are eager to find out about how planet systems were formed around stars. They want to probe into the hearts of galaxies and see the regions right around the black hole that's accreting material and ultimately shining away as a quasar. In order to do that and look back to distant regions in the universe or penetrate dense clouds of dust nearby, you need enormous light gathering power and very high, what we call resolution, sharpness in the image. And so this telescope combines both those aspects. Itís the worldís largest telescope. It has two enormous primary mirrors acting in concert and when the light of the two mirrors is focused together, it will give that very sharp resolution allowing us images that are ten times sharper than Hubbleís space telescope can take now.

So there are two big challenges in a project like this. One is achieving the performance goal of combining the light of these two giant mirrors so precisely that we align light waves with crest to crest and trough to trough. That requires holding the relative position of all these giant optical elements to extraordinary accuracy having no vibrations getting through the system and this requires high-precision control in a way thatís not been done before. So thatís going to be the biggest technical challenges to achieve the ultimate performance here. The other general challenge was that you can see from the shape and size of this telescope nothing like this has ever been built before and so each piece required new technical innovation and met its own set of challenges.